PROJECT SUMMARY/ABSTRACT Ultrasound is, and is poised to remain, a ubiquitous biomedical imaging modality. It is safe, fast, effective, and affordable. Ultrasound imaging innovations are being actively developed to provide inexpensive solutions to public health concerns in areas as diverse as early cancer detection, targeted drug delivery, and image-guided surgery. Yet significant barriers to research and innovation in diagnostic ultrasound persist. An ultrasound machine is a highly integrated system with hardware, software, and algorithmic subsystems. Innovators and researchers need access to all subsystems to efficiently and effectively develop new technologies, but no clean path exists for this. ?Research grade? systems allow access to raw data but not the underlying hardware or software, while tying users to a specific manufacturer for support and hardware development. The lack of a truly open system for ultrasound development discourages?and likely prohibits? participation, raises the cost of new research and development, and prolongs the timeline from the research laboratory to the clinic. As a consequence, ultrasound's potential is less effective and efficient, limiting its contributions to improve public health. A better approach is needed. In keeping with NIBIB's mission to promote ultrasound as a broad-based imaging tool, Creare and its collaborators at the University of Illinois Urbana-Champaign (UIUC) and the University of California, San Diego (UCSD) plan to develop an open-sourced, modular, ready-to-use hardware and software platform for ultrasound imaging development. Our hypothesis is that this platform will speed up and spur innovation, reduce the cost of future research, enable new multidisciplinary collaborations, and provide a common framework to assess new technologies and algorithms. Researchers, engineers, and innovators will have free and unrestricted access to all hardware schematics and circuit board layouts; to the firmware and application interface source codes; and to a framework for integrating new processing algorithms. The platform will be tied together by an online community that hosts the system documentation, schematics, and source code; provides a mechanism for incorporating new, user-contributed designs and features; and includes a forum for the open sharing of ideas and data, troubleshooting issues, and promoting new collaborations and applications. The goal of this Phase I application is to develop, evaluate, and open source an initial prototype ultrasound imaging system with a supporting online platform.